Tuesday, 13 May 2014

Pop-up wetlands

The idea of ‘Pop –up’ or
’walking wetlands’ has been used in North America for a number of years. They
are temporary wetlands where land, usually agricultural, is shallowly flooded
to attract waterbirds. This has achieved benefits for both conservation and
agriculture. They have been used by conservationists to provide feeding habitat
for passage waders or wildfowl. The large concentrations of Snow Geese or cranes that can occur on these sites are well known.

Why do we not seem to employ
similar techniques in the UK? Okay these are not natural habitats but where
feeding opportunities for birds are lacking, such temporary wetlands are likely
to attract large numbers of birds. We
could adapt these ideas on nature reserves. Where a reserve lacks suitable
shallow floods in the autumn but has available water, why not pump water up
into a temporary scrape? Can we not flood cropped areas to provide autumn
habitat for waterbirds?

Dungeness is already employing
a variation of this technique with some success. The ‘hay fields’ at Denge
Marsh flood naturally with high water levels but when they are low, water
can be pumped into the fields from the adjacent ditches.I took a trip down to ‘Dunge’ last week to
look at these fields.They have already
attracted a flock of 10 Black-winged Stilts this year and a Long-billed Dowitcher was
briefly present on the day of my visit. Sadly whilst I was enjoying the delights of 2
booming Bitterns, several Hobbies, Whimbrel, Common and Arctic Terns, the Dowitcher
flew away.Arriving at the hay fields,
we discussed how management could be improved (to tempt Dowitchers to stay longer). This year, the fields will be
drained by June in preparation for cutting the vegetation in early July and then
several areas will be rotovated. Water
will be pumped back on in late July and the area maintained wet into next
spring. This should provide not only
good early autumn feeding for passage waders and other waterbirds but also
allow early colonisation by chironomids to enable a sufficiently large biomass of
larvae by next spring for breeding waders.

A grizzled old ecologist/birder, usually to be found roaming around the Lee Valley and occasionally further afield. Fortunate to be involved in the management of some of the UK's finest nature reserves and always looking for ways of improving them for birds.